In the field of automated load handling vehicles, the degree of flexibility is often the key factor in determining the usefulness of the system. Automated load handling vehicles receive, carry, and place loads in a variety of applications. However, oftentimes an automatic load handling vehicle which operates effectively in one application cannot adjust to a different application. Of course numerous factors determine the overall flexibility of an automated load handling system, including: the organization of the operating environment, the programmability of the load handling system, and the physical architecture of both the operating environment and the load handling vehicle. For example, if the programmability of a load handling vehicle is relatively low, then the organization of its operating environment should be relatively high to produce efficient results. Since attempting to organize every operating environment is difficult and expensive, the programmability of automated load handling systems is increasing in order to adapt to changing operating environments.
One important attribute for flexible load handling systems is the ability to automatically recognize, receive, and carry a load. Automated load handling systems employ markedly different loading systems. Many of these loading systems are directed towards a specific application, while others are adaptable to various applications. Automated forklift vehicles, for instance, find usefulness in a diversity of applications. Some prior loading systems for automated vehicles, such as forklifts, rely on an organized operating environment in order to receive a load. For instance, a warehouse having all loads positioned at a given height allows a vehicle to position its load carrying portion at the given height when loading. Other loading systems, such as that disclosed in U.S. Pat. No. 4,520,443 issued May 28, 1985 to Yuki et al., offer greater flexibility. The loading and unloading system includes a lift height sensor, a tilt sensor, and a load sensor. As a result of the outputs of these sensors, the fork height and the tilt angle of the lifting mast are controlled to facilitate the loading and unloading operations performed by the vehicle. U.S. Pat. No. 4,331,417 issued May 25, 1982 to Shearer, Jr. further senses the location of the load. This system controls the horizontal and vertical alignment of a load handling vehicle for loading and unloading. A triangular target, which is recognizable by a similarly designed sensor unit on the vehicle, is placed on each load. The horizontal position of the vehicle and the height of the forks are adjusted until alignment of the sensor with a given target is achieved.
Yet greater flexibility is needed. A truly autonomous vehicle should be able to recognize a load without relying on a target mechanism. Targets may deteriorate thus becoming ineffective, while adding cost to the overall load handling system. Furthermore, accurate positioning of the load carrying implement depends on the positioning of the target. Damage to the vehicle or the load is a possible result of inaccurate target location. In fact if the target is misaligned, the load recognition system cannot align with the target, and therefore cannot receive the load.
The present invention is directed to overcoming one or more of the problems as set forth above.